Pregnancy Glossary

A user-friendly guide to the pregnancy and childbirth terms you need to know.


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active labor Thinning and opening of the cervix, usually between 4–10 centimeters, with contractions typically 2–5 minutes apart

afterbirth Placenta and membranes expelled by the uterus after the baby is delivered

alpha-fetoprotein test (AFP) Blood test given between the 15th and 20th weeks of pregnancy to screen for abnormalities, including neural-tube defects and Down syndrome

amniocentesis Extracting a sample of the amniotic fluid to test for fetal abnormalities

amniotic fluid The fluid inside the amniotic sac (aka bag of water) that surrounds and protects the baby during pregnancy

anterior presentation The most common position for babies during birth, with the face turned toward the mother's spine


back labor Contractions primarily felt in the mother's lower back; sometimes caused when the baby is facing the mother's front

blastocyst The fertilized egg (zygote) once it enters the uterus

Braxton-Hicks contractions False labor pains that occur throughout pregnancy

breech birth When the baby's buttocks, knees or feet appear first during delivery; usually results in a Cesarean section


cephalopelvic disproportion (CPD) When a baby's head is too large to fit through the mother's pelvis

cerclage A stitch placed in a weak cervix to help prevent premature delivery

cervical incompetence Premature opening of the cervix (without contractions)

cervical ripening Softening and thinning of the cervix in preparation for labor

cervix The narrow lower end of the uterus

Cesarean section (C-section) Surgical removal of the baby and placenta through an incision made in the mother's uterus

chloasma (mask of pregnancy) Brownish patches that sometimes develop on the face during pregnancy

chorionic villus sampling (CVS) Removal of a small amount of tissue from the placenta to test for chromosomal or metabolic abnormalities; usually performed between weeks 10–12

colostrum Fluid produced by the breasts in the latter months of pregnancy (and soon after birth); transfers proteins and immunities to the baby

contractions (labor pains) Tightening of the uterus to expel the baby; contractions become stronger and more frequent as labor progresses

cord compression Squeezing of the umbilical cord that leads to slowing or interruption of blood flow to the fetus

crowning When the baby's head has descended so far into the birth canal that it can be seen


diastasis A vertical separation of the two halves of the abdominal muscles that can occur in late pregnancy

dilation Opening of the cervix during labor to allow the baby to pass through; 10 centimeters is considered fully dilated

Down syndrome A genetic disorder caused by extra chromosomes and characterized by mental retardation, medical problems and abnormal facial features

dystocia Slow-progressing, difficult labor


eclampsia (toxemia) A life-threatening high-blood-pressure condition marked by seizures and coma; usually occurs after the 20th week and can only be "cured" by delivering the baby

ectopic pregnancy Implantation of the fertilized egg in a place other than the uterine wall, usually in a fallopian tube

effacement Gradual thinning and shortening of the cervix during labor

embryo The developing fertilized egg until the eighth week of pregnancy

epidural A spinal injection that numbs the lower half of the body to decrease or eliminate pain during labor; the catheter that delivers the drugs is left in place

episiotomy A surgical incision in the perineal area to widen the vaginal opening for delivery; the procedure is increasingly considered unnecessary or even harmful

external version The attempt to manually move a breech baby into the head-down position


failure to progress A slow or stopped labor

fetal distress (nonreassuring fetal status) When the baby does not move for a time or has a slower-than-normal heartbeat; may indicate he is not receiving enough oxygen

fetal monitor Device used to listen to and record the heartbeat of the fetus; normal range is 110–160 beats per minute

fetus The developing baby from the end of the eighth week of pregnancy until birth

forceps delivery Placing spoon-like instruments around the baby's head to facilitate delivery

foremilk The breast milk the baby gets during the first few minutes of nursing; it has a high volume and low fat concentration

full term A baby born after the 36th week

fundus The top of the uterus; after 20 weeks, the height in centimeters is generally equal to the number of weeks a woman is pregnant


gestational age The fetus's age measured from the first day of the mother's last menstrual period; an average pregnancy lasts 280 days, or about 40 weeks, from that day

gestational diabetes Diabetes that arises during pregnancy; usually subsides after delivery


hindmilk The milk a baby gets after the first few minutes of nursing; it's lower in volume, but higher in calories and fat

human chorionic gonadotropin (hCG) A hormone produced by the embryo and thought to be related to nausea in early pregnancy

hyperemesis gravidarum Very severe nausea and vomiting during pregnancy


induction Using artificial means to start labor, such as puncturing the membranes or giving oxytocin (Pitocin)


kick count A record kept during late pregnancy of the number of times a fetus moves over a certain period of time


labor stages 1: from the onset of labor until the cervix is completely thinned and dilated; 2: the pushing stage, during which the baby emerges from the vagina; 3: expulsion of the placenta and membranes

laboring down Allowing a mother who's had an epidural to hold back from pushing until she has the urge or until certain signs of readiness to deliver appear

lactation Milk production by the breasts

large for gestational age A newborn weighing approximately 9 3/4 pounds or more

latching on When a baby takes the nipple and areola properly into his mouth to nurse

letdown reflex The breasts' release of milk for the nursing baby

lightening Dropping of the fetus deeper into the pelvis in the weeks prior to birth

linea nigra A dark line that can appear from the navel to the pubic bone during pregnancy

lochia Vaginal discharge after delivery

low birthweight A baby weighing less than 5 1/2 pounds at birth


membranes The amnion and chorion, which make up the amniotic sac

miscarriage The spontaneous loss of a pregnancy before the fetus can survive outside the uterus; most common in the first trimester

morning sickness Nausea and vomiting, usually occurring during the first 13 weeks of pregnancy

mucus plug A jellylike plug that seals off the cervix and is expelled before delivery


neonate The newborn until 4 weeks of age

neural-tube defect A birth defect, such as spina bifida, that results from improper development of the brain, spinal cord or their coverings

nonreassuring fetal status (fetal distress) Concern that the baby is not receiving sufficient oxygen from the placenta


obstructed labor Slowing or cessation of labor

oxytocin (Pitocin) A drug used to help start or intensify labor contractions


pelvic-floor muscles Muscles that help support the vagina, uterus, bladder, urethra and rectum; can be strengthened by Kegel exercises

perineum The area between the vagina and anus; an incision here to facilitate delivery is called an episiotomy

pica The urge to eat nonfood items

placenta Tissue that connects the mother to her fetus and provides nourishment to and takes away waste from the baby

placental abruption Premature separation of the placenta from the uterus prior to delivery, often causing bleeding or severe, premature contractions; requires an emergency C-section

placenta previa A condition in which the placenta lies very low in the uterus so that the opening of the uterus is partially or completely covered; may require a C-section

posterior presentation When the back of the baby's head presses on the mother's back; causes "back labor" and may make pushing difficult

post-term pregnancy A pregnancy that lasts beyond 42 weeks from the first day of the mother's last menstrual period

preeclampsia A complication involving high blood pressure, swelling and abnormal kidney function; occurs after the 20th week and, left untreated, can lead to seizures and even death

premature baby A baby born before 37 weeks

preterm labor Labor that starts after 20 weeks but before the end of the 37th week

prolapsed cord Slipping of part of the umbilical cord into the birth canal during delivery; can result in oxygen deprivation to the baby


quickening When the mother first feels the fetus move, usually between weeks 18–22


rooting reflex When touching a baby's lips or stroking his cheek causes the baby to open his mouth and turn his head toward the stimulus

round-ligament pain Pain caused by stretching of the ligaments surrounding the uterus

rupture of membranes (breaking of waters) Breaking of the membranes that make up the amniotic sac during or before labor


show Vaginal discharge, often mucus and blood, that occurs as labor approaches

spinal anesthesia Numbing of the lower half of the body; unlike an epidural, the catheter is not left in place

station The relationship of the baby's head during labor to bony knobs in the pelvis; positive numbers indicate delivery is closer


transition stage The period during labor when the cervix dilates from 8–10 centimeters

transverse lie When the baby lies crosswise in the uterus

trial of labor Choosing to attempt a vaginal birth after having had a prior C-section

trimesters 1: up to 14 weeks; 2: 14–27 weeks; 3: 28 weeks–delivery


ultrasound (sonogram) A device that uses high-frequency sound waves to produce a picture of the fetus in utero

umbilical cord The structure that connects the baby's bloodstream to the mother's


vacuum extraction The use of suction to help guide the baby's head out of the birth canal

VBAC Vaginal birth after C-section


zygote A fertilized egg; becomes embryo